Carburetor



Jan. 7, 1936. c. POGUE 7 2,025,798

CARBURETOR Filed Sept. 2'7, 1935 2 Sheets-Sheet 1 Char 66$ N Poy Jan. 7, 1936. 5, N P E 2,026,798

' CARBURETOR I Filed Sept. 27, 1935 2 Sheets-Sheet 2 N 1 (D N Charles NP y J Patented 7,1936

UNITED STATES PATENT OFFICE Application September 27, 1935, Serial 190.42.540

8 Claims. (01. 261-13) This invention relates to carburetors suitable for use with internal combustion engines and is an improvement on the carburetors shown in my Patents Nos.- 1,938,497, granted December 5,

1933, and 1,997,497, granted April 9, 1935.

In my aforesaid patents an intimate contact between a liquid such as the fuel used for internal combustion engines. and a gas, such as air, is obtained by causing the gas to bubble up through a body of the liquid. The vaporized liquld passes into a vapor chamber which preferably is heated, and any liquid droplets are returned to the body of liquid, with the result that the fuel introduced into the combustion chambers is free of liquid particles, and in the molecular state so that an intimate mixture with the air is obtained to give an explosive mixture from which nearer the maximum energy contained in the liquid fuel is obtained. Moreover, as there are no liquid particles introduced into the combustion chambers there will be no burning of the fuel and consequently the temperature of the engine will not be increased above that at which it operates most efficiently.

In my Patent No. 1,997,497, the air which is to bubble up through the body of liquid fuel is forced into and through the fuel under pressure and the fuel vapors and air pass into a chamber where they are heated and caused to expand. The introduction of the air under pressure and the expansion of the vaporous mixture insures a sumcient pressure being maintained in the vapor heating and expanding chamber to cause at least a portion of it to be expelled therefrom into the intake manifold as soon as the valve controlling the passage thereto is opened.

In accordance with the present invention, improved means are provided for maintaining the vaporous mixture in the vapor heating chamber under a predetermined pressure, and for regulating such pressure so that it will be at the optimum for the particular conditions under which the engine is to operate. Such means preferably comprises a reciprocating pump operated by a vacuum-actuated motor for forcing the vapors into and through said chamber. lihe pump is provided with a suitable pressure-regulating valve so that when the pressure in the vapor-heating chamber exceeds the predetermined amount a portion of the vaporous mixturewill be by-passed from the outlet side to the inlet side of the pump and recirculated.

The invention will be described further in connection with the accompanying drawings, but such further disclosure and description is to be taken merely as an exemplification of the invention, and the same is not limited thereby except as is pointed out in the subjoined claims.

In the drawings:

Fig. 1 is a side elevation of a carburetor embodying the invention.

Fig, 2 is a plan view thereof.

Fig. 3 is an enlarged vertical sectional view.

Fig. 4 is a transverse sectional view on the line 5 H of Fig. 3.

Fig. 5 is a detail sectional view on line 5-5 of Fig. 3.

Fig. 6 is a transverse sectional view through the pump and actuating motor therefor, taken on 10 line 6-6 of Fig. 2.

Fig. 7 is a longitudinal sectional view through the pump, taken on line 7-4 of Fig. 2, and

Fig. 8 is a longitudinal sectional view through a part of the pump cylinder, showing the piston 5 in elevation.

In the accompanying drawings, a vaporizing and atomizing chamber I is located'at the bottom of the carburetor and has an outlet at its top for the passage of fuel vapors and air into a 20 primary vapor heating chamber 2.

The vaporizing chamber I is provided with a perforated false bottom 3 and is normally filled .with liquid fuel to the level indicated in Fig. 1. Atmospheric air from a conduit 4 is introduced into the space below the false bottom 3 and passes upwardly through the body of liquid fuel below the false bottom 3, and then through the perforations 5 in said false bottom, which breaks it up into a myriad of fine bubbles, which pass upwardly through the liquid fuel above the false bottom.

Liquid fuel for maintaining the level indicated in the chamber I passes from the usual fuel tank (not shown) through a pipe 6, and is forced by a pump 1 through a pipe 8 into and through a. pair of nozzles 9 having their outlets located in the chamber I, just above the-level of the liquid fuel therein. The pump I may be of any approved form but is preferably of the diaphragm type, as such fuel pumps are now standard equipment on most automobiles.

The nozzles 9 are externally threaded at their lower ends to facilitate their assembly in the chamber I and to permit them to be removed readily, should cleaning be necessary;

The upper ends of the nozzles 9 are surrounded by Venturi' tubes Ill having baflies II located at their upper ends opposite the outlets of the nozzles, as is shown and described in detail in my aforesaid Patent No. 1,997,497. The liquid fuel being forced from the ends of the nozzles 9 into the restricted portions of the Venturi tubes causes a rapid circulation of the air and vapors in the 55 chamber through the tubes I0 and brings the air and vapors into intimate contact with the liquid fuel, with the result that a portion thereof is vaporized. Unvaporized portions of the liquid fuel strike the baifles II and are thereby further so to the pipe 6 on the intake side of the pump 1.

Such an arrangement permits a large amount of liquid fuel to be circulated by the pump 1 without more fuel being withdrawn from the fuel tank than is actually vaporized and consumed in the engine. As thedtloat valve l2 will set upon the end of the outlet pipe It as soon as the liquid level drops below the indicated level, there is no danger of vapors passing into the pipe i4 and v hence into the pump 1 to interfere with its normal operation.

The amount of liquid fuel vaporized by the nozzles 9 and by, the passage of air through the liquid body thereof is sufllcient to provide a suitably enriched vaporous mixture for introducing into the passage leading to the intake manifold of the engine through which the main volume of atmospheric air passes.

Vapors formed by the atmospheric air bubbling through the liquid fuel in the bottom of the chamber l and those formed as the result of the atomization at the nozzles 9 pass from the top of that chamber into the primary heating chamher 2. As is clearly shown in Fig. l, the chamber 2 comprises a relatively long spiral passage l5 through which the vaporous mixture gradually passes inwardly to a central outlet G6 to which is connected a conduit ll leading to a reciprocating pump l8 which forces'the vaporous mixture under pressure into a conduit is leading to a central inlet 20 of asecondary heating chamber 2i which like the primary heating chamber comprises a relatively long spiral. The vaporous mixture gradually passes outwardly through the spiral chamber 2| and enters a downdraft air tube 22, leading to the intake manifold of the engine, through an outlet 23 controlled by a rotary plug valve 24.

To prevent the engine from backfirlng into the vapor chamber 2, the ends of the passages 89 are covered-with a line mesh screen 25, which, operating on the principle of a miners lamp, will prevent the vapors in the chamber 2 from exploding in case of a. backfire, but will not interfere substantiallywith the passage of the vapors from the chamber 2| into the air tube 23 when the valve 24 is in open position. The air tube 22 preferably is in the form of a venturi with the greatest restriction being at that point where the outlet 23 is located, so that when the valve 24 is opened there will be a pulling force on the vaporous mixture due to the increased velocity of the air at the restrictedportion of the air tube opposite the outlet 23, as well as an expelling force on them due to the pressure maintained in ing medium such as the gaseous products of combustion from the exhaust manifold.

The pump I! for forcing the vaporous mixture from the primary heating chamber 2 into and through the secondary chamber 2| includesa ea, to which is connected the outlet pipe I910 which conducts the vaporous mixture under pressure to the secondary heating chamber 2|. Each of the valves 32, 34, 35 and 31 is of the one-way type. They are shown as being gravity-actuated flap valves, but it will be understood that springpressed or other types of one-way valves may be used if desired.

One side of the piston 30 is formed with a gear rack 39 which is received in a groove 39a of the wall forming the cylinder of a the pump. The gear rack 39 engages with an actuating spur gear d0 carried on one end of the shaft 4! and operating in a housing 42 formed on the pump cylinder. The other end of the shaft ll carries a spur gear 63, which engages and is operated by a gear rack M carried on a piston 66 of a double-acting motor M. The particular construction of the double-acting motor 41 is not material, and it may be of a vacuum type commonly used for operating windshield wipers on automobiles, in which case a flexible hose 68 would be connected with the intake manifold of the engine to provide the necessary vacuum for operating the piston 45. Under the influence of the double-acting motordl, the piston 30 of the pump has a reciprocatory movement in the working chamber 29. Movement of the piston towards the left in Fig. '7 tends to compress the vaporous mixture in the working chamber between the end of the piston and the inlet from the pipe l1, and causes the 40 valve 35 to be forced tightly against the inlet opening. In a like manner, the valves 32 and 34 are forced open and vaporous mixture in that portion of the working chamber is forced through the inlet 3! in the end of the piston 30, into the interior of the piston, where it displaces the vaporous mixture there and forces it into the space between the right-hand end of the piston and the right-hand end of the working chamber. The passage of the vaporous mixture into the right- 5 hand and of the working chamber is supplemented by the partial vacuum created there when the piston moves towards the left. During such movement of the piston; the valve 31 is maintained closed and prevents any sucking back of the vaporous mixture from the secondary heating chamber 2|. When the motor 61 reverses, the piston 30 moves to the right and the vaporous mixture in the right-hand end of the working chamber is forced past the valve 3'! and through the pipe l9 into the secondary heating chamber 2|. At the same time, a vacuum is created behind the piston 30 and results in the left-hand end of the working chamber again being filled with the vaporous 65 mixture from the primary heating chamber 2. As the operation of the pump 61 will vary in accordance with the suction created in the intake manifold, it preferably is regulated to actuate the pump at such a speed that the vaporous mixture will always be pumped into the secondary heating chamber at a rate sufllcient to maintain a greater pressure there than is desired. In order that the pressure in the working chamber may at all times be maintained at the optimum, a pipe 7 acne-res ill having an adjustable pressure-regulating valve Si is connected across the inlet and outlet pipes I1 and is. The valve ii will permit a portion of the vaporous mixture discharged from the pump to be bypassed to the inlet II so that a pressure, predetermined by the seating of the valve II, will at all times be maintained in the second heating chamber II.

The air tube 22 is provided with a butterfly throttle valve 52 and a choke valve 53. as is usual with carburetors adapted for use with internal combustion engines. Operating stems N, 55, 5G

' for the valves 52, II and 24 respectively, extend An operating arm I1 is through the casing 28. fixedly secured to the outer end of the stem 55 and is connected to a rod ll which extends to the dashboard of the automobile or some other place conveniently located to the driver of the automobile. The outer endof the stem it of the valve 24 which controls the outlet 23 from the secondary heating chamber II has one end of an operating arm as fixedly secured thereto. The other end of the arm 59 is pivotally connected to a link 60 which extends downwardly and pivotally connects to one end of a bell crank lever 6|, fixedly secured to the end of the stem it of the throttle valve 52. The other end of the bell crank lever BI is connected to an operating rod 2 which, like the rod 58, extends to a. place conveniently located to the driver. The valves 14 and 52 are connected for simultaneous operation so that when the throttle valve 52 is opened to increase the speed of the engine the valve 24 will be opened to admit a larger amount of the heated vaporous mixture from the secondary heating chamber 2 I.

While the suction created by the pump ll ordinarily will create a suflicient vacuum in the primary heating chamber 2, to cause atmospheric air to be drawn into and upwardly through the body of liquid fuel in the bottom of the vaporizing chamber i, in some instances it may be desirable to provide supplemental means for forcing the atmospheric air into and through said body of liquid and in such cases an auxiliary pump may be provided for that purpose, or the air conduit 4 may be provided with a funnel-shaped intake which is positioned behind the fan 83 which is customarily placed behind the radiator of the engine.

The foregoing description has been given in connection with a downdraft type of carburetor, but it is to be understood that the invention is not limited to use with such type carburetors and that the manner in which the mixture of atmospheric air and vapors is introduced into the engine cylinders is immaterial as fuse the advantages of the carburetor are concerned.

Before the carburetor is put into use the pressure-regulating valve Si in the bypass pipe 50 will be adjusted so that the pressure best suited for conditions under which the engine is to operate will be maintained in the secondary heating chamber 2i. When the valve 5i has thus been set and the engine started, the pump l8 will create a partial vacuum in the primary heating chamber 2 and cause atmospheric air to be drawn through the conduit l and to bubble upwardly through the liquid in the bottom of the vaporizing and atomizlng chamber I with resultant vaporization of a part of the liquid fuel therein. At the same time, the pump 1 will be set into operation and liquid fuel will be pumped from the fuel tank through the nozzles a which will result in an additional amount of the fuel being vaporized. The vapors resulting from .23 which opens into the air tube 22 which con- 1 such atomization of the liquid fuel and the passage of the air through the body of the liquid will pass into and through the spiral chamber i where they will be heated by the products of combustion in the surrounding chamber formed 5 bythe casing 28. Thefuelvapors andairwill gradually pass inwardly to the outlet i8 and thence through the conduit II to the pump II which will force them into the secondary heating chamber 2| inwhichtheywill be maintained at the predetermined pressure by the pressureregulatlng valve ii. Thevaporous-mixture is further heatedin the chamber 2| and spirally outwardly to the valve-controlled outlet ducts the main volume of atmospheric air to the intake manifold of the engine.

The heating of the vaporous mixture in the heating chambers I and II tends to cause them to expand, but expansion in the chamber 2| is prevented due to the pressure maintained in that chamber by the regulating valve 8|. However. as soon as the heated va rous mixture passes the valve l4 and is introduced into the air flowing through the intake tube 22, it is free 25 to expand and thereby become relatively li ht so that a more intimate mixture with the air is obtained prior to the mixture being exploded in the engine cylinders. Thus it will beseen that the present invention not only provides :0

it leaves the chamber 2i it will expand to such as an extent as to have a density less than it would if introduced directly from the vaporizing and atomizlng chamber i into the air tube 22.

The majority of the liquid particles entrained by the vaporous mixture leaving the chamber 40 I will be separated in the first half of the outermost spiral of the primary heating chamber 2 V and drained back into the body of liquid in the tank i. Any liquid particles which are not thus separated will be carried on with the vaporous 4,5 mixture and due to the circulation of that mixture and the application of heat, will be vaporized before the vaporous mixture is introduced into the air tube 22 from the secondary heating chamber 2i. Thus dry vapors only are in so troduced into the engine cylinders and any burning of liquid particles of the fuel in the engine cylinder, which would tend to raise the temperature of the engine above that at which it operates most emciently is avoided.

While the fullest benefits ofthe invention are obtained by using both a primary and a secondary heating chamber, the primary heating chamber may, if desired, be eliminated, and the vaporous mixture pumped directly from the va- 60 porizing and atomizlng chamber l into the spiral heating chamber 2|. 4

From the foregoing description it will be seen that the present invention provides an improvement over the carburetor disclosed in my afore- 05 said Patent 1,997,497, in that it is possible to maintain the vaporous mixture in the heating chamber 2i under a predetermined pressure, and that as soon as the vaporous mixture is introduced into the main supply of air passing to the 70 intake manifold of the engine, it will expand and reach a density at which it will form a more intimate mixture with the air. Furthermore, the introduction of the vaporous mixture into theairstreaminthetubeflcausesacertain" amount of turbulence which also tends to give a more intimate mixture of the vapor molecules with the air.

'I claim:

1. A carburetor for internal combustion engines comprising a vaporizing chamber, means for vaporizing fuel therein, a vapor-heating chamber, a pump for pumping vapors from the vaporizing chamber into the vapor-heating chamber, a bypass for fuel vapors from the outlet side of said pump to the inlet side thereof, means for maintaining vapors in said vaporheating chamber during normal operation of 'the let side of the pump to the inlet side thereof, a

pressure-regulating valve in said bypass forv maintaining vapors in said vapor-heating chamber during normal operation of the carburetor under predetermined pressure, a passage for atmospheric air adapted to communicate with the intake manifold of the engine, and means for introducing vapors from said vapor-heating chamber into said atmospheric air passage.

3. A carburetor for internal combustion engines comprising a vaporizing chamber, means for vaporizing fuel therein, a primary vapor-heating chamber, a secondary vapor-heating chamber, means for conducting vapors from the vaporizing chamber to the primary vapor-heating chamber, means for conducting vapors from the primary vapor-heating chamber to the secondary vaporheating chambenmeans for maintaining vapors in said secondary vapor-heating chamber during normal operation of the carburetor under a predetermined superatmospheric pressure, means for varying the pressure at which vapors are maintained in said secondary vapor-heating chamber independently of the speed of the engine, a passage for atmospheric air adapted to com municate with the intake manifold of the engine, and means for introducing vapors from said secondary vapor-heating chamber into said atmospheric air passage.

4. A carburetor for internal combustion engines comprising a vaporizing chamber, means for vaporizing fuel therein, a vapor heating chamber,

means for conducting vapors from the vaporizing chamber into the vapor-heating chamber, means for maintaining vapors in said vapor-heating chamber during normal operation of the carburetor under superatmospheric pressure, means for varying the pressure at which vapors are maintained in said vapor-heating chamber independently of the speed of the engine, and means in chamber whereby said air will bubble upwardly through the liquid fuel and vaporize a portion thereof, a vapor-heating chamber, means for conducting vapors from the vaporizing chamber into the vapor-heating chamber, means for maintain- 5 ing vapors in said vapor-heating chamber during normal operation of the carburetor under a predetermined superatmospheric pressure, means for varying the pressure at which vapors are maintained in said vapor-heating chamber lndepend- 1 ently of the speed of the engine, and means for introducing vapors from said vapor-heating chamber into the intake manifold of the engine.

6. A carburetor for internal combustion engines comprising a vaporizing chamber, means for 15 maintaining a body of liquid fuel in the bottom of said chamber, means for introducing atmospheric air into the body of liquid in the vaporizing chamber whereby said air will bubble upwardly through the liquid fuel and vaporize a 20 portion thereof, a primary vapor-heating chamber, a secondary vapor-heating chamber, means for passing vapors from the vaporizing chamber to the primary vapor-heating chamber, means for conducting vapors from the primary vapor-heating chamber to the secondary vapor-heating chamber, means for maintaining vapors in said secondary vapor-heating chamber under pressure, and means for introducing vapors from said secondary vapor-heating chamber into theintake 30 manifold of the engine.

'7. A carburetor for internal combustion engines comprising a vaporizing chamber, .means for maintaining a body of llquidfuel in the bottom of said chamber, means for introducing atmospheric 35 air into the body of liquid in the vaporizing chamber whereby said air will bubble upwardly through the liquid fuel and vaporize a portion thereof,

a spiral primary vapor-heating chamber, a spiral .secondary-vapor-heating chamber, means for 40 passing vapors from the vaporizing chamber into an outer spiral of the primary vapor-heating chamber, means for passing vapors from the center of the primary vapor-heating chamber to the center of the secondary vapor-heating chamber, and means for passing vapors from an outer spiral of the secondary vapor-heating chamber to the intake manifold of the engine.

8. A carburetor for internal combustion engine comprising a vaporizing chamber, means for maintaining a body of liquid fuel in the bottom of said chamber, means for introducing atmospheric air into the body of'liquld in the vaporizing chamber whereby said air will bubble upwardly through the liquid fuel and vaporize a portion thereof, atomizing nozzles positioned in said atomizing chamber, means for forcing liquid fuel through said atomizing nozzles whereby an additional amount of liquid fuel is vaporized, a primary vapor-heating chamber, a secondary vapor-heating 0 chamber, means for passing vapors from the vaporizing chamber to the primary vapor-heating chamber, means for passing vapors from the primary vapor-heating chamber to the secondary en ine.

cnanrns N. POGUE. 

